The period corresponding to ovulation is called the fertile period, occurring approximately fourteen days after the first day of the last menstrual period, in women whose menstrual cycle is 28 days. It is at this point that a woman is more likely to become pregnant, as one or more eggs are released by the ovary to be fertilized by sperm.
It is based on this principle that the table method is done.
However, even in people with a fully regulated cycle, there is no way to predict whether ovulation will occur at exactly this time. Thus, if she wants (or not) to become pregnant, it may be important that the woman also pays attention to some signs that the body points out.
One is temperature. When we ovulate, there is an increase in progesterone in the bloodstream, raising the temperature around 0.2 to 0.5 degrees. Considering this fact, when doing this measurement daily, and at the same time, it is easy to notice such a change. This increase usually starts two or three days before ovulation, returning to its normal value after the onset of bleeding. Another clue is related to cervical mucus. At this time it tends to be thicker, clearer, crystalline and elastic; indicating the production of estrogen.
Thus, the period between these events and the next three days is the most favorable for a pregnancy to occur. Considering that sperm can survive for up to approximately three days in a woman's body, sexual intercourse a few days before that time also allows for a future pregnancy.
By Mariana Araguaia
Graduated in Biology
Source: Brazil School - https://brasilescola.uol.com.br/sexualidade/dia-fertil.htm